Insulin Aspart, Human: Everything You Need to Know

Insulin Aspart is a rapid-acting insulin analog used to control blood sugar in people with type 1 and type 2 diabetes — it's injected before meals and starts working within about 15 minutes to help your body process the sugar from food.

Whether you've just been prescribed Insulin Aspart or you're trying to learn more about your treatment options, this guide covers everything you need to know in 2026: what it is, how it works, how to take it, what it costs, and more.

What Is Insulin Aspart?

Insulin Aspart is a rapid-acting insulin analog — a lab-made version of the insulin your body naturally produces. It's designed to work faster than regular human insulin so it can control the blood sugar spike that happens after you eat.

Brand and Generic Names

• NovoLog — the most widely known brand name
• Fiasp — a faster-acting version of Insulin Aspart (also by Novo Nordisk)
• NovoLog Mix 70/30 — a combination of rapid-acting and intermediate-acting insulin
• Generic Insulin Aspart — available since Novo Nordisk authorized generic versions

Drug Class

Insulin Aspart belongs to the rapid-acting insulin class. Other drugs in this class include Insulin Lispro (Humalog) and Insulin Glulisine (Apidra).

Manufacturer

Insulin Aspart is manufactured by Novo Nordisk, a Danish pharmaceutical company and one of the world's largest insulin producers.

FDA Approval

NovoLog was approved by the FDA for use in the United States. Fiasp, the faster-acting formulation, received separate FDA approval. Both are approved for adults, and NovoLog is also approved for children age 2 and older with type 1 diabetes.

Controlled Substance Status

Insulin Aspart is not a controlled substance. You do need a prescription to get it, but it doesn't carry DEA scheduling restrictions.

What Is Insulin Aspart Used For?

FDA-Approved Uses

• Type 1 diabetes — In adults and children age 2+, Insulin Aspart is used as mealtime (bolus) insulin alongside a longer-acting basal insulin to manage blood sugar throughout the day.
• Type 2 diabetes — In adults whose blood sugar isn't adequately controlled with oral medications or basal insulin alone, adding mealtime Insulin Aspart can help manage post-meal blood sugar spikes.

Off-Label Uses

Doctors sometimes use Insulin Aspart for conditions beyond its official FDA approval, including:

• Diabetic ketoacidosis (DKA) — a serious complication of diabetes treated in hospital settings
• Hyperkalemia — dangerously high potassium levels (insulin drives potassium into cells)
• Gestational diabetes — diabetes during pregnancy, where insulin is preferred over oral medications

How Is Insulin Aspart Taken?

Dosage Forms

Insulin Aspart comes in several forms:

• Vial — 10 mL vial, 100 units/mL (U-100), used with insulin syringes
• FlexPen — prefilled disposable pen, 3 mL, 100 units/mL
• FlexTouch — prefilled disposable pen, 3 mL, 100 units/mL
• PenFill cartridge — 3 mL cartridge for use in compatible pen devices
• NovoLog Mix 70/30 — combination insulin in FlexPen
• Fiasp — available as vial and FlexTouch pen

Typical Dosing

Doses are individualized based on your blood sugar levels, meals, and activity. General guidelines:

• Type 1 diabetes: Total daily insulin is typically 0.4-1 unit per kilogram of body weight per day, split roughly 50/50 between basal insulin and mealtime Insulin Aspart.
• Type 2 diabetes: Starting doses are often 4 units per meal, 0.1 units/kg per meal, or 10% of your basal insulin dose.

Your doctor will adjust your dose based on your blood sugar readings, A1C, and other factors.

How to Inject

• Inject subcutaneously (under the skin) — not into a vein or muscle
• NovoLog: Inject 5-10 minutes before starting a meal
• Fiasp: Inject at the start of a meal or within 20 minutes after starting a meal
• Rotate injection sites: thighs, upper arms, abdomen, and buttocks
• Do not inject into skin that is damaged, tender, bruised, or scarred
• Always eat after injecting — skipping a meal after taking rapid-acting insulin can cause dangerous low blood sugar
• Never share pens, cartridges, or syringes with another person, even if the needle is changed

Insulin Aspart can also be used in insulin pumps (continuous subcutaneous insulin infusion) for both NovoLog and Fiasp formulations.

Who Should Not Take Insulin Aspart?

Do not use Insulin Aspart if you:

• Are allergic to Insulin Aspart or any of its ingredients
• Are currently experiencing hypoglycemia (low blood sugar) — treat the low first

Use with caution if you have:

• Kidney disease — your body may clear insulin more slowly, increasing hypoglycemia risk
• Liver disease — insulin metabolism may be affected
• A history of severe allergic reactions to insulin products

Always tell your doctor about all your medical conditions and medications before starting Insulin Aspart. For a full list of potential interactions, see our guide on Insulin Aspart drug interactions.

How Much Does Insulin Aspart Cost?

The cost of Insulin Aspart varies widely depending on whether you have insurance, which formulation you need, and where you fill your prescription.

Without Insurance

• Brand NovoLog: $130-$350 per vial or pen pack
• Generic Insulin Aspart: Around $152 retail, but as low as $74 with a GoodRx coupon

With Insurance

• Most commercial insurance and Medicare Part D plans cover Insulin Aspart
• Medicare patients: Pay no more than $35 per month for insulin under the Inflation Reduction Act
• Many commercial plans also have insulin cost caps
• Prior authorization is generally not required

Savings Programs

• Novo Nordisk Savings Card: Commercially insured patients can pay as little as $35/month for NovoLog or Fiasp (up to 3 vials or 2 packs of pens). Available at novolog.com/savings.
• Novo Nordisk Patient Assistance Program (NovoCare): Free insulin for qualifying uninsured or underinsured patients. Apply at novocare.com.
• Novo Nordisk cut the U.S. list price of NovoLog by 75% starting January 1, 2024.

For a complete breakdown of savings options, see our guide on how to save money on Insulin Aspart.

Current Availability in 2026

Some Insulin Aspart formulations are affected by an ongoing shortage. Fiasp FlexTouch pens have been in shortage since 2024, and the unbranded generic was discontinued at the end of 2025. If you're having trouble finding your specific formulation, use Medfinder to check pharmacy stock near you.

Final Thoughts

Insulin Aspart, Human is a well-established, effective rapid-acting insulin used by millions of people with diabetes. Understanding how it works, how to take it correctly, and what it costs puts you in a better position to manage your diabetes and work effectively with your healthcare team.

If you're looking for a doctor who can prescribe Insulin Aspart, check out our guide to finding a prescriber near you. And for information on how Insulin Aspart works at a deeper level, see our mechanism of action guide.